RANGSIT, Thailand — Beside a wall of white sandbags that has become a front line in Thailand's battle to prevent an epic season of monsoon floods from reaching Bangkok, needlefish swim through knee-high water inside Sawat Taengon's home.

On one side, a cloudy brown river pours through a canal diverting water around the Thai capital, just to the south.

On the other side, homes just like his are unscathed. Whether floodwaters breach fortified barriers like these this weekend will decide whether Bangkok will be swamped or spared.

As of late Saturday at least, the alarmed metropolis of glass-walled condominiums and gilded Buddhist temples remained unscathed, and authorities were confident it would narrowly escape disaster.

"We just hope it doesn't go higher," said Sawat, a 38-year-old construction worker whose home had the misfortune of being inside the vast sandbag wall, which runs at least 2.5 miles along a canal in Rangsit, just north of Bangkok's city limits.

A group of U.S. Marines arrived Saturday to help assess the situation and what help could be offered by the United States.

Prime Minister Yingluck Shinawatra's government says most of Bangkok, which lies about six feet above sea level, sits safely behind an elaborate system of flood walls, canals, dikes and seven underground drainage tunnels that were completed over the last year.

The latest floods are posing the biggest test those defenses have ever faced.

Adisak Kantee, deputy director of Bangkok's drainage department, reported encouraging signs Saturday. Runoff from the north had decreased slightly and high tides that could have impeded critical water flows to the Gulf of Thailand have not been severe as expected, he told The Associated Press.

Water levels along the main Chao Phraya River and key canals to the north in places like Rangsit are still manageable, he said.

Dams near full capacity
On a bridge above a flooded canal in Rangsit, Army Col. Wirat Nakjoo echoed the need to be vigilant.

"The worst is not over," he said. "The dams are at near full capacity and there's still a lot of water that needs to be released."

Government workers there were taking no chances, stacking new sandbags atop a canal-side wall about 4.5 feet high.

The government says the floods, which have killed 297 people, are the worst to hit the Southeast Asian kingdom in half a century.

In a radio address Saturday, Yingluck called them "the worst in Thai history."

Monsoon deluges that have pounded Thailand since late July have affected 8 million people and swept across two-thirds of the country, drowning agricultural land and swallowing low-lying villages along the way.

More than 200 major highways and roads are impassable, and the main rail lines to the north have been shut down. Authorities says property damage and losses could reach $3 billion dollars.

Thailand's lucrative tourist destinations — beaches and islands like Koh Samui, Krabi and Phuket — have not been affected, though, and its international airports remain open.

In the last few days, government officials have voiced increasing confidence the capital would survive without major damage, but those assurances have failed to stop Bangkokians from raiding supermarket shelves to stock up on bottled water, dried noodles, flashlight batteries and candles.

Marines bring sandbags, water
Subway gates have been sealed with steel barriers. Worried car owners are cramming vehicles into high-rise parking spaces at the city's malls and airports. Some international hotels and street-side shops have barricaded their entranceways with sandbags — not knowing where or when or even if flooding will occur.

But life in Bangkok remains normal, and the calm contrasts sharply with heavily flooded neighboring provinces, including Ayutthaya and Pathum Thani, where Rangsit is located. Television stations broadcasting images of swamped towns — showing waterlogged residents in canoes and braving chest-high water — have inadvertently fueled fears of imminent doom in the capital.

The 10-man team of U.S. Marines arrived Saturday on a survey mission to determine how Washington can offer help, U.S. Embassy spokesman Walter M. Braunohler said.

The Marines were traveling aboard an American military cargo jet full of bottled water and sandbags needed to reinforce flood barriers.

In Rangsit, Sawat said floods occur nearly every year, though never this bad. The water in the canal beside his home began rising a month ago, he said, and the sandbags have risen along with it.

Last week, his family began shifting their valuables to higher ground after flood waters seeped in. Now, his wife and four children move through their home atop makeshift wooden planks that allow them to avoid the water lapping below.

"It's going to get higher," he said. "We need to be prepared."

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